Transforming growth factor beta 1 and latency-associated peptide in PR-A and PR-B mice mammary glands. (a) Examples of dual immunofluorescence staining to latency-associated peptide (LAP) (green) and transforming growth factor beta 1 (TGFβ1) (red) in mammary glands derived from wild-type (WT) and PR-A transgenic mice; both were decreased in the transgenic mice. Nuclei were counterstained with 4',6-diamino-2-phenylindole (DAPI). (b) Quantitative image analysis of the intensity of LAP and TGFβ1 immunoreactivity per cell in mammary glands of PR-A mice. Both LAP and TGFβ1 had a lower intensity in cells derived from PR-A transgenic mice as compared with WT controls (P < 0.001 in both cases). (c) Quantitative image analysis of the intensity of LAP and TGFβ1 immunoreactivity per cell in PR-A mice versus PR-B mice. Only the increase in LAP in PR-B mice compared with PR-A mice was statistically significant (P < 0.001). The difference in active TGFβ1, although increased in PR-B mice, was not statistically significant.